The present invention concerns an artificial ice structure constructed in an offshore frigid environment.
Artificial gravel, sand and silt islands have been constructed in the polar regions to serve as a base for drilling, producing and related oilfield operations. However, in most such offshore areas the construction period is limited to the brief summer season. Also, dredging operations using available materials introduce high construction costs.
The present invention provides an improved base for oilfield operations and/or a road system in offshore polar regions. In such regions, out to about sixty feet of water depth, a continuous sheet of ice, known as fast ice, forms in the winter to a maximum thickness of about seven feet. Although fast ice appears to be stationary, it can move at rates of several feet per hour with a seasonal movement of as much as one hundred feet or more. The artificial structure must have sufficient mass, in combination with other defensive measures, to resist the forces imposed by movement of the fast ice and to provide maximum well protection in the event lateral forces due to movement of the fast ice should cause the ice structure to move. A silo well bore protection system, which may also be utilized with artificially formed non-ice structures, extends through the ice structure and into the sea floor and houses separable well control equipment located below the sea floor.